Pre-formed hydrogels made of gelling agents provide unique benefits to various consumer products due to its formed, yet flexible physical characteristics. Pre-formed hydrogel patch and mask devices are useful for cosmetic and dermatological treatment products such as for delivering skin care actives, percutaneously deliverable pharmaceuticals, and for promoting healing of burns or wounds. Edible pre-formed hydrogel sheets and objects provide nutritional products and snacks having distinctive appearance, taste, and oral texture; and oral administrative pharmaceuticals.
Particularly in the skin treatment area, the use of specialty cosmetics such as packs and masks are increasing in popularity in that they are effective, relatively safe, and reasonably priced compared to other treatments such as chemical peeling, laser surgery, photofacial, and others. PCT publication WO 01/78678 and co-pending U.S. application Ser. No. 60/339,287 relate to a pre-formed hydrogel product for effectively delivering skin benefit agents to the skin, hair or nails, the device comprising a skin benefit agent in the form of a coating composition for the pre-formed hydrogel.
While these pre-formed hydrogel products are suitable for delivering a variety of skin benefit agents to the skin, there are certain skin benefit agents and other chemical compounds that cannot be formulated with the product, as being unstable with the pre-formed hydrogel. For example, certain compounds react with the pre-formed hydrogel and enhance syneresis, enhance stiffening, or produce unaesthetic color and/or odor. All of these results may significantly affect product performance and/or aesthetics. Such factors limit the scope of compounds that can be formulated with the pre-formed hydrogel products.
Based on the foregoing, there is a need for a pre-formed hydrogel product that can be formulated with a wide variety of compounds, and can be suitably used by the consumer. Further, there is a need for such a product that can be provided at low cost.
None of the existing art provides all of the advantages and benefits of the present invention.